Safety assembly for a syringe

Abstract

A safety support device for a syringe comprises a support sheath for the body of the syringe and an inner sheath suitable for sliding relative to the support sheath between a waiting, retracted position and the extended position for protecting the needle of the syringe. The device has means for holding the syringe body relative to the support sheath and retaining means suitable for being activated to retain g the inner sheath in the waiting, retracted position inside the support sheath and for being deactivated by the piston of the syringe to allow the inner sheath to extend into its protective, extended position.

The invention claimed is: 
     
       1. A safety syringe support system comprising,
 a) a first rigid sheath having a proximal end opposite a distal front end; 
 b) a second rigid sheath having a proximal end opposite a distal front end; 
 c) a pre-stressed spring biasing the first and second sheaths to move independently and relative to each other, where the pre-stressed spring has a loaded position and an unloaded position; 
 d) an abutment surface at the proximal end of the first sheath; and 
 e) at least two resilient tongues extending axially and proximally from the proximal end of the second sheath and in snap fit engagement with the abutment surface, where the two resilient tongues are configured to flex radially disengaging from the abutment surface and allowing the pre-stressed spring to unload and to move one sheath relative to other sheath, 
 wherein the first sheath and the second sheath are non-collapsible and form overlapping concentric tubes when the pre-stressed spring is in both the loaded and unloaded positions and neither sheath comprises a syringe body, and 
 wherein one of the two sheaths is configured to engage and hold a syringe body inside the sheath when the syringe body is inserted into the sheath from the proximal end such that the syringe body is surrounded by the sheath. 
 
     
     
       2. The safety syringe support of  claim 1  further characterized in that a snap fastening rib is formed behind the abutment surface, where the snap fastening rib is configured to accept a collar of an injection syringe. 
     
     
       3. A safety syringe support system comprising;
 a) a first rigid sheath having a proximal end opposite a distal front end; 
 b) a second rigid sheath having proximal end opposite a distal front end, where both sheaths share a common longitudinal axis A; 
 c) a spring biasing the first and second sheaths to move independently and relative to each other from a start to a final position; and 
 d) at least two resilient tongues extending axially and proximally from the proximal end of one of the sheaths configured to flex radially outwardly away from axis A allowing the spring to move one sheath relative to other sheath, 
 wherein the first sheath and the second sheath are non-collapsible and form concentric tubes and neither sheath comprises a syringe body and where the start position is configured such that when a syringe and needle assembly is mounted in the first sheath the needle will project beyond the distal front of the second sheath and where the final position is configured such that when a syringe and needle assembly is mounted in the first sheath, the second sheath forms a protective shield all around the needle and both sheaths enclose both the needle and the syringe. 
 
     
     
       4. A safety syringe support system containing a syringe assembly comprising
 a) a syringe assembly comprising a syringe pre-filled with medicament, an injection needle and a piston, where the syringe has a collar; 
 b) a first rigid sheath comprising a snap rib configured to engage the collar of the syringe and to axially fix the syringe assembly with the first sheath; 
 c) a second rigid sheath, where the first and second sheaths are configured to move independently and relative to each other from a start position to a final position, where each sheath has a proximal end opposite a distal front end and where the needle projects outwardly beyond the distal front ends of both sheaths when the sheaths are in the start position; 
 d) a pre-stressed loaded spring in contact with the both sheaths; 
 e) at least two resilient tongues extending axially and proximally from the proximal end of one of the sheaths where each tongue terminates in a ramp having a bearing surface and are configured to flex radially outward away from a longitudinal axis common to both sheaths allowing the first sheath to move relative to the second sheath from the start position to the final position as the spring begins to unload, 
 wherein the first sheath and the second sheath are non-collapsible and form concentric tubes and neither sheath comprises a syringe body, and 
 wherein one of the two sheaths is configured to engage and hold a syringe body inside the sheath when the syringe body is inserted into the sheath from the proximal end such that the syringe body is surrounded by the sheath. 
 
     
     
       5. The safety syringe support system of  claim 4  further including,
 a two-part lock having a first part on the first sheath and a second part on the second sheath, where the lock is engaged when sheaths are in the final position preventing the sheaths from moving relative to each other and where the second sheath forms a protective shield all around the needle. 
 
     
     
       6. The safety syringe support system of  claim 4  further characterized in that the tongues have hooks that engage the other sheath in the start position and that disengage when the tongues flex radially. 
     
     
       7. A safety syringe support system comprising,
 a) a first rigid sheath having a proximal end opposite a distal front end; 
 b) a second rigid sheath having proximal end opposite a distal front end and a collar projecting radially outward from a longitudinal axis A common to both sheaths, the collar configured to provide support surfaces for an index and middle finger of user of the safety support system; 
 c) a spring biasing the first and second sheaths to move independently and relative to each other, where the spring has a loaded position and an unloaded position; and 
 d) at least two resilient tongues extending axially and proximally from the proximal end of one of the sheaths configured to flex radially allowing the spring to move one sheath relative to other sheath, 
 wherein the first sheath and the second sheath are non-collapsible and form overlapping concentric tubes when the spring is in both the loaded and unloaded positions and neither sheath comprises a syringe body, and 
 wherein one of the two sheaths is configured to engage and hold a syringe body inside the sheath when the syringe body is inserted into the sheath from the proximal end such that the syringe body is surrounded by the sheath.